One of the biggest mysteries is the origins of Lion, a gem-like creature which Rose Quartz entrusted with her most prized possessions. Lion's presence in the show has lead to many different fan theories about his identity. So here's the most plausible ideas about who Lion might really be, and why he had such a close relationship with Rose Quartz.

Bismuth

The contents of Lion's pocket dimension were revealed in the episode Lion 3: Straight To Video, and one of the items stood out to fans as a possible gem: bismuth.

The mysterious object and bismuth.

This is very interesting, as bismuth's chemical properties could have huge implications for the plot of Steven Universe. In early alchemical texts, bismuth was described as an elemental "seed" for creating new environments. If the Steven Universe writers wanted to incorporate this, that could mean this bismuth-like object in Lion's mane was used in the gem progeny process, maybe in creating the Kindergartens.

But moving on from this, it's possible that this is actually a corrupted or dormant gem, and that Bismuth is a character like the Crystal Gems. Considering that the object is held in a gem bubble this is certainly possible, and has lead some fans to theorise that Lion himself is actually Bismuth.

Bismuth by Khozen on Tumblr

But if Lion is Bismuth, why is he (or she) not manifesting a humanoid physical form like the other Crystal Gems? It's possible that Bismuth's gem is corrupted, and Rose's bubble is preventing it from deteriorating further. Maybe Lion's animal shape is the only way it can manifest while its gem is held in the bubble.

Pink Pearl

The pearls are one of the most interesting of Gem classes: as "made-to-order servants", the pearls serve higher ranking gems on Homeworld. Peridot explained the pearls' purpose in Back To The Barn...

"They're for standing around, and looking nice, and holding your stuff for you."

The "holding your stuff comment" is very interesting as so far, Pearl is the only other gem to use a pocket dimension like Lion's.

Pearl's pocket dimension.

So could Lion actually be a pearl? Lennat on Tumblr theorises that this could be the case, and that Lion is the pearl who used to serve the as-yet unseen Pink Diamond.

"Who, and where, is Pink Pearl? Patterns thus far would indicate that she would have a pink color scheme and be able to hide things within herself. She also would have had a very obvious affiliation with Rose Quartz, who either is Pink Diamond or belonged to her court. Incidentally, one character fits that description perfectly: Lion."

This actually makes a lot of sense. After all, gems can change their physical form to become something other than humanoid. This would also explain why our Pearl didn't know of Lion's existence.

Pearl isn't happy with Lion

It's possible that Lion was meant to be somewhat undercover, a safeguard to protect the things (and people) Rose Quartz valued most. Or maybe Pink Pearl appeared as Lion to protect her own identity after she betrayed Pink Diamond. The plot possibilities are exciting, and even if this theory doesn't turn out to be true, it definitely makes for an interesting plot twist! Unless, of course, Lion is Rose Quartz herself...

Eidlon on Reddit takes this one step further, suggesting that Lion could be an offshoot of Rose Quartz's creation of Steven.

"To create Steven from a part of his dad, Rose had to anchor him to something stable- her gem. Bringing him into the world meant her body had to let go of the gem, it was the only physical part of her she could contribute to her son. Perhaps Lion is that other part of rose, the body that isn't the gem. It didn't just dissipate, but instead lost focus without its guiding intelligence. Lion isn't Rose, but a part of her left to run wild."

This would explain how Lion knew about Rose Quartz's secret armory, and why Lion chose to stay with and protect Steven.

Lion carries Steven and Connie

It would also explain Lion's pink coloring, and why although sentient, he doesn't possess the kind of intelligence the Crystal Gems have.

And the rest...

There are plenty more theories about who Lion could be. He could be another corrupted gem shard, which Rose Quartz partially healed. Or even Pink Diamond herself, hiding in plain sight! And of course, Lion could just be Lion, another magical creature from Homeworld which we don't know the origins of yet. Which would explain why he is so cat-like in his behavior!

Whatever Lion's origins, it'll be exciting to find out who Lion is, even if he's just Rose's animal familiar.